4. During which period did the first modern birds appear? Estimate the date in millions of years (Ma).

Cretaceous period

Explanation:

Fossil records suggest that modern birds originated 60 million years ago, after the end of the Cretaceous period about 65 million years ago when dinosaurs died off

answer; i believe that the correct answer is (b) melosis; plz check first.good luck

voluntary muscles are controlled by the cerebellum.